In her new book "What Happened" — officially out on September 12 — Hillary Clinton wrote that her biggest regret from the the campaign trail was saying that she would put coal miners out of business.
CNN, which obtained a copy of the book this week, reported that the 2016 Democratic presidential nominee said that comment was the one "I regret the most."
Clinton made the remark during a town hall in Columbus, Ohio in March 2016, during which she touted her plan to replace fossil fuel-based energy production with renewable systems.
"I'm the only candidate which has a policy about how to bring economic opportunity using clean renewable energy as the key into coal country," she said. "Because we're going to put a lot of coal miners and coal companies out of business."